1. Field of the Invention
This invention relates generally to right angle measurement in construction and, and more particularly to a carpenter's square with features for alignment of boards and for defining a pair of orthogonal directions and a related corner.
2. Description of Related Art
The following art defines the present state of this field:
Swanson, U.S. Pat. No. 3,492,737 describes an extensible rule having a plurality of telescopically engaged channel sections. The rule is provided with quickly detachable attachments for extending the range of its functional capabilities. The sections, except the outermost section, are frictionally slidable within each other nested in telescoping relationship. Each section had a flat web and side walls lying in planes normal to that of the web. Shallow recesses are formed in the outer surfaces and graduated strips are positioned in the recesses. The outermost section is a rectangular tube with a closed rear wall for enclosing the other inner sections when the other sections are completely retracted within the outermost section.
Simuro et al., U.S. Pat. No. 4,194,295 describes an attachment for a carpenter's folding ruler that has an elongated body with a longitudinal slot. The slot is dimensioned to accept the ruler and the ends of the body have flat sections against which part of the ruler can be folded to form certain angles. One of the ends makes a 90.degree. angle with the axis of the slot while the other ends is at some angle less than 90.degree.. A level is provided on the body so that it may be vertically or horizontally positioned.
Wilson, U.S. Pat. No. 4,729,173 describes an adjustable carpenter's square that is formed by having a main beam with a head secured to an upper portion of the main beam with a slide secured to the upper end of the main beam. The head and the slide are partially rotatably secured to the main beam. The head and the slide are slideably and adjustably connected to each other also in addition to being connected to the head.
Walters, U.S. Pat. No. 5,269,066 describes an improved hand tool comprising a generally L-shaped frame having two legs each formed with a pair of channels spaced apart by a central ridge, and having panels of transparent material, such as tempered glass or plastic, mounted in the channels with a quantity of a suitable liquid contained between the panels to define a level-indicating chamber extending substantially the entire length of each leg and having indicia positioned adjacent the ends of each of these chambers to provide information relating to incremental discrepancies.
Kunz, U.S. D314,712 describes the ornamental design for a T-square with centering ruler.
Groves, U.S. D260,616 describes the ornamental design for an adjustable carpenter's square.
The prior art teaches a variety of tools capable of enabling the alignment of boards and other construction materials at a right angle as for defining a corner of a construction. The prior art also teaches the use of construction stakes for defining a corner of a construction. However, the prior art does not teach a carpenter's square having a conformation and shape capable of easily aligning common boards by the use of U-shaped channels. The prior art also does not teach the use of such a square for defining a right angle in a construction line. The present invention fulfills these needs and provides further related advantages as described in the following summary.